• Molecules and Cells
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• v.45 no.10
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• pp.702-717
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• 2022

Hepatitis C virus (HCV) infection can lead to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV employs diverse strategies to evade host antiviral innate immune responses to mediate a persistent infection. In the present study, we show that nonstructural protein 5A (NS5A) interacts with an NF-κB inhibitor immunomodulatory kinase, IKKε, and subsequently downregulates beta interferon (IFN-β) promoter activity. We further demonstrate that NS5A inhibits DDX3-mediated IKKε and interferon regulatory factor 3 (IRF3) phosphorylation. We also note that hyperphosphorylation of NS5A mediates protein interplay between NS5A and IKKε, thereby contributing to NS5A mediated modulation of IFN-β signaling. Lastly, NS5A inhibits IKKε-dependent p65 phosphorylation and NF-κB activation. Based on these findings, we propose NS5A as a novel regulator of IFN signaling events, specifically by inhibiting IKKε downstream signaling cascades through its interaction with IKKε. Taken together, these data suggest an additional mechanistic means by which HCV modulates host antiviral innate immune responses to promote persistent viral infection.

• BMB Reports
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• v.47 no.6
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• pp.318-323
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• 2014

We isolated the phenolic glucoside salicortin from a Populus euramericana bark extract, and examined its ability to suppress inflammatory responses as well as the molecular mechanisms underlying these abilities, using lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Salicortin inhibited iNOS expression and the subsequent production of NO in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells. Salicortin significantly suppressed LPS-induced signal cascades of NF-${\kappa}B$ activation, such as IKK activation, $I{\kappa}B{\alpha}$ phosphorylation and p65 phosphorylation in RAW 264.7 cells. In addition, salicortin inhibited the LPS-induced activation of JNK, but not ERK or p38 MAPK. Furthermore, salicortin significantly inhibited production of pro-inflammatory cytokines, such as TNF-${\alpha}$, IL-$1{\beta}$ and IL-6 in the LPS-stimulated RAW 264.7 cells. These findings suggest that salicortin may show its anti-inflammatory activity by suppressing the LPS-induced expression of pro-inflammatory mediators through inhibition of NF-${\kappa}B$ and JNK MAPK signaling cascades in macrophages.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.481-487
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• 2007

Toll-like receptors (TLRs) induce innate immune responses that are essential for host defenses against invading microbial pathogens, thus leading to the activation of adaptive immune responses. In general, TLRs have two major downstream signaling pathways: the MyD88- and TRIF-dependent pathways, which lead to the activation of $NF-{\kappa}B$ and IRF3. Numerous studies have demonstrated that certain phytochemicals possessing anti-inflammatory effects inhibit $NF-{\kappa}B$ activation induced by pro-inflammatory stimuli, including lipopolysaccharides and $TNF{\alpha}$. However, the direct molecular targets for such anti-inflammatory phytochemicals have not been fully identified. Identifying the direct targets of phytochemicals within the TLR pathways is important because the activation of TLRs by pro-inflammatory stimuli can induce inflammatory responses that are the key etiological conditions in the development of many chronic inflammatory diseases. In this paper we discuss the molecular targets of resveratrol, (-)-epigallocatechin-3-gallate (EGCG), and curcumin in the TLR signaling pathways. Resveratrol specifically inhibited the TRIF pathway in TLR3 and TLR4 signaling, by targetting TBK1 and RIP1 in the TRIF complex. Furthermore, EGCG suppressed the activation of IRF3 by targetting TBK1 in the TRIF-dependent signaling pathways. In contrast, the molecular target of curcumin within the TLR signaling pathways is the receptor itself, in addition to $IKK{\beta}$. Together, certain dietary phytochemicals can modulate TLR-derived signaling and inflammatory target gene expression, and in turn, alter susceptibility to microbial infection and chronic inflammatory diseases.

• Journal of Applied Biological Chemistry
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• v.62 no.2
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• pp.111-122
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• 2019

The mulberry tree (Morus alba L.) has been traditionally used in Chinese medicine to treat inflammatory diseases. We investigated the effects of bioconversion on different components of the mulberry tree, and determined changes in the physiological activities. Ethyl acetate-soluble fractions of five different segments (fruit, Mori Fructus; leaf, Mori Folium; twig, Mori Ramulus; root, Mori Cortex; and mistletoe, Loranthi Ramulus) of the mulberry tree show enhanced anti-oxidant effects in the 2,2-diphenyl-1-picrylhydrazyl, and 2,2'-azinobis-(3-ethylvenzothiazoline-6-sulfonic acid) assays, and enhanced anti-inflammatory effects of lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production in RAW 264.7 macrophages, after being treated with a crude enzyme extract from Aspergillus kawachii, in the following order of activity: Mori Folium>Mori Cortex>Mori Ramulus>Mori Fructus>Loranthi Ramulus. Ethyl acetate- soluble fraction of mulberry leaves (Mori Folium) that underwent bioconversion was most effective, and was devoid of any cytotoxicity. The fraction was also effective against mRNA expression of LPS-induced pro-inflammatory cytokines, such as inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis $factor-{\alpha}$, $interleukin-1{\beta}$, and interleukin-6. In addition, the fraction was effective in LPS-induced phosphorylation of mitogen-activated protein kinases and IKK, and $I{\kappa}B$ degradation, followed by translocation of the nuclear $factor-{\kappa}B$ from the cytoplasm to the nucleus. Thus, bioconversion increased the anti-oxidative and anti-inflammatory activities of the mulberry leaf.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.57-66
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• 2019

The ethyl acetate fraction of Bat Faeces (Ye Ming Sha: natural products used in Chinese Medicine) after fermentation (EFBF-AF) showed enhanced anti-oxidative effects in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt assays. Fermentation of the Bat Faeces by using the crude enzyme extract from Aspergillus kawachii, significantly increased the anti-inflammatory effects. Fermented Bat Faeces markedly inhibited nitric oxide production, inducible nitric oxide synthase, and cyclooxygenase-2 expression in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The EFBF-AF reduced the nuclear translocation of nuclear factor kappa B ($NF-{\kappa}B$) via $IKK{\alpha}$ and $I{\kappa}B{\alpha}$ phosphorylation, and decreased the phosphorylated the extracellular signal-regulated kinases (ERK) and p38 expression in LPS-treated RAW 264.7 macrophages. In addition, the EFBF-AF suppressed the expression of pro-inflammatory genes, such as interleukin-$1{\beta}$, interleukin-6, and tumor necrosis $factor-{\alpha}$. These results suggest that fermented Bat Faeces may suppress pro-inflammatory responses in LPS-stimulated RAW 264.7 macrophages cells via ERK, p38 mitogen-activated protein kinase and $NF-{\kappa}B$ signaling pathways.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.443-449
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• 2023

The purpose of this study was to observe cell death in human keratinocytes stimulated against the infectious cytokines TNF-α and IFN-γ, and to observe the expression of Phospho-NF-κB due to phosphorylation of IkB to confirm the mechanism of inhibiting the expression of inflammatory cytokines. As a result of cell viability analysis, differences in PEMF stimulation time were observed little by little after 1 hour, 3 hours, 6 hours, 12 hours, 24 hours, and 48 hours, but there was no statistical significance according to PEMF stimulation time for each time (p>0.05). No significant difference was observed in the total amount of NF-κB present in the cytoplasm and nucleus, but a significant decrease in the expression of phosphorylated NF-κB was observed in the group exposed to PEMF stimulation for 24 hours (^*p<0.05). The expression of IL-1β was observed in all inflammation-induced groups, and the concentration of IL-1β compared to α-Tubulin expression was reduced by about 54% in the PEMF-stimulated group for 24 hours compared to the control group (^***p<0.001). As a result of the study, it is shown that PEMF stimulation does not negatively affect HaCaT cells from 0 to 48 hours and can inhibit the expression of inflammatory cytokines by inhibiting the pathway of NF-κB.

• Journal of Acupuncture Research
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• v.22 no.3
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• pp.155-167
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• 2005

Objectives : The purpose of this study was to investigate the anti-inflammatory effect of Cobrotoxin on binding affinity of cobrotoxin with P50, $IKK{\alpa}$ and $IKK{\beta}$, activities of NF-${\kappa}B$, Cell viability of astrocyte, expressions of protein molecules of NF-${\kappa}B$ such as P50, P-$1{kappa}B$, $1{\kappa}B$ and iflammation related genes such as Cox-2, iNOS, cPLA2 in the SNP or LPS induced Inflammatory pathway of Rats' astrocytes. Methods : In this study, The expression of cytosolic phospholipase A2, Nitric oxcide, Cyclooxygenase-2 and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of NF-${\kappa}B$ was assayed by EMSA method in astrocytes of rats. The Cell viability of astrocytes was determined by MTT assay, and Binding affinity of Cobrotoxin with P50, $IKK{\alpha}$ and $IKK{\beta}$ was assayed by Surface plasmon resonance analysis, and NF-${\kappa}B$ dependent luciferase activity was determined by luciferase analysis, and Uptake of cobrotoxin in astrocytes was identified by Confocal laser scanning microscope Results : 1. Compared with control, LPS-induced NF-${\kappa}B$ DNA binding activity was decreased significantly by 0.1, $0.5{\mu}g/m{\ell}$ of Cobrotoxin in Astrocyte. 2. Compared with control, LPS-induced NF-kB dependent luciferase expression was decreased significantly by 0.1, 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin in Astrocyte. 3. Compared with control, SNP induced P50, $I{\kappa}B$ expressions in astrocyte were decreased significantly by 0.1, 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin and P-$1{\kappa}B$ expression was decreased significantly by 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin. 4. Compared with control, LPS induced P50, $1{\kappa}B$ expressions in astrocyte were decreased significantly by 0.5 and $1{\mu}g/m{\ell}$ of Cobrotoxin. 5. Compared with control, SNP induced Cox-2, iNOS, CPLA2 expressions in astrocyte were decreased significantly by $1{\mu}g/m{\ell}$ of Cobrotoxin. 6. Compared with control, LPS induced Cox-2, cPLA2 expressions in astrocyte were decreased significantly by 0.1, 0.5, $1{\mu}g/m{\ell}$ of Cobrotoxin and iNOS expression was decreased significantly by 0.5, $1{\mu}g/m{\ell}$ of Cobrotoxin. 7. Compared with $0.5{\mu}g/m{\ell}$ of Cobrotoxin, SNP-induced NF-${\kappa}B$ DNA bindins activity in astrocyte was increased significantly by Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 1mM and Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 5mM. 8. Compared with $0.5{\mu}g/m{\ell}$ of Cobrotoxin, LPS-induced NF-${\kappa}B$ DNA binding activity in astrocyte was increased significantly by Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 1mM, Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 5mM, Cobrotoxin $0.5{\mu}g/m{\ell}$with GSH 1mM and Cobrotoxin $0.5{\mu}g/m{\ell}$ with GSH 5mM 9. Compared with $0.1{\mu}g/m{\ell}$ of cobrotoxin, SNP induced P50 expressions in astrocyte were increased significantly by Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 1mM, Cobrotoxin $0.5{\mu}g/m{\ell}$ with DTT 5mM Cobrotoxin $0.5{\mu}g/m{\ell}$ with GSH 1mM and Cobrotoxin $0.5{\mu}g/m{\ell}$ with GSH 5mM. 10. The uptake of the labeled cobrotoxin into the cells was shown under a confocal laser scanning microscope. cobrotoxin was uptaken into the membrane and nucleus of astrocytes. Conclusions : In summary, the present results demonstrate that cobrotoxin directly binds to sulfhydryl group of p50 and IKKS resulting In the reduction of translocation of p50 and IkB release, thereby inhibits activation of NF-${\kappa}B$, and suggest that pico to nanomolar range of cobrotoxin could inhibit the expression of genes in the NF-${\kappa}B$ signal pathway.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.175-180
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• 2007

Toll-like receptors induce innate immune responses recognizing conserved microbial structural molecules that are known as pathogen-associated molecular patterns (PAMPs). Ligand-induced homotypic oligomerization was found to proceed in LPS-induced activation of TLR4 signaling pathways. TLR2 is known to heterodimerize with TLR1 or TLR6 and recognize diacyl- or triacyl-lipopeptide, respectively. These results suggest that ligand-induced receptor dimerization of TLR4 and TLR2 is required for the activation of downstream signaling pathways. Therefore, receptor dimerization may be one of the first lines of regulation in the activation of TLR-mediated signaling pathways and induction of subsequent innate and adaptive immune responses. Here, we report biochemical evidence that curcumin from the plant Curcuma longa inhibits activation of $NF-{\kappa}B$, expression of COX-2, and dimerization of TLRs induced by TLR2, TLR3 and TLR4 agonists. These results imply that curcumin can modulate the activation of TLRs and subsequent immune/inflammatory responses induced by microbial pathogens.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.475-482
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• 2009

Rifampicin is a macrocyclic antibiotic which is used extensively for treatment against Mycobacterium tuberculosis and other mycobacterial infections. Recently, a number of studies have focused on the immune-regulatory effects of rifampicin. Therefore, we hypothesized that rifampicin may influence the TLR2 expression in LPS-activated RAW 264.7 cells. In this study, we determined that rifampicin suppresses LPS-induced TLR2 mRNA expression. The down-regulation of TLR2 expression coincided with decreased production of TNF-$\alpha$ Since NF-${\kappa}B$ is a major transcription factor that regulates genes for TLR2 and TNF-$\alpha$, we examined the effect of rifampicin on the LPS-induced NF-${\kappa}B$ activation. Rifampicin inhibited NF-${\kappa}B$ DNA-binding activity in LPS-activated RAW 264.7 cells, while it did not affect IKK$\alpha/\beta$ activity. However, rifampicin slightly inhibited the nuclear translocation of NF-${\kappa}B$ p65. In addition, rifampicin increased physical interaction between pregnane X receptor, a receptor for rifampicin, and NF-${\kappa}B$ p65, suggesting pregnane X receptor interferes with NF-${\kappa}B$ binding to DNA. Taken together, our results demonstrate that rifampicin inhibits LPS-induced TLR2 expression, at least in part, via the suppression of NF-${\kappa}B$ DNA-binding activity in RAW 264.7 cells. Thus, the present results suggest that the rifampicin-mediated inhibition of TLR2 via the suppression of NF-${\kappa}B$ DNA-binding activity may be a novel mechanism of the immune-suppressive effects of rifampicin.

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.332-336
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• 2008

Ginger is widely used as a traditional herbal medicine. Both ginger and its extracts have been used to treat many chronic inflammatory conditions via the inhibition of nuclear factor-kappa B (NF-${\kappa}B$) activation, which results in the suppression of cyclooxygenase-2 (COX-2) expression. However, the mechanisms as to how ginger extracts mediate their health effects are largely unknown. Toll-like receptors (TLRs) trigger anti-microbial innate immune responses, recognizing conserved microbial structural molecules that are known as pathogen-associated molecular patterns. All TLR signaling pathways culminate in the activation of NF-${\kappa}B$. The activation of NF- ${\kappa}B$ leads to the induction of inflammatory gene products, including cytokines and COX-2. This study reports the biochemical evidence that 6-shogaol, an active compound in ginger, inhibits NF-${\kappa}B$ activation and COX-2 expression induced by TLR2, TLR3, and TLR4 agonists. Furthermore, 6-shogaol inhibited NF-${\kappa}B$ activation induced by the following downstream signaling components of the TLRs: MyD88, $IKK{\beta}$, and p65. These results imply that ginger can modulate immune responses that could potentially modify the risk of many chronic inflammatory diseases.